Fate of the Universe, Age of the Universe, Dark Matter, and the Decaying Vacuum Energy

It is shown that in the cosmological models based on a vacuum energy decaying as a^{-2}, where a is the scale factor of the universe, the fate of the universe in regard to whether it will collapse in future or expand forever is determined not by the curvature constant k but by an effective curvature constant k_{eff}. It is argued that a closed universe with k=1 may expand forever, in other words simulate the expansion dynamics of a flat or an open universe because of the possibility that k_{eff}=0 or -1, respectively. Two such models, in one of which the vacuum does not interact with matter and in another of which it does, are studied. It is shown that the vacuum equation of state p_{vac}= -\rho_{vac} may be realized in a decaying vacuum cosmology provided the vacuum interacts wuth matter. The optical depths for gravitational lensing as a function of the matter density and other parameters in the models are calculated at a source redshift of 2. The age of the universe is discussed and shown to be compatible with the new Hipparcos lower limit of 11Gyr. The possibility that a time-varying vacuum energy may serve as dark matter is suggested.Comment: AAS LaTex, 29 pages, published in the Astrophysical Journal, 520, 45, 199

Understanding Transient-Member Nonprofit Organizations

This paper reports on an examination of membership nonprofits whose members are committed for a relatively short period—“transient-member nonprofits.” These organizations are pressured to attend to the current membership and long-term projects are difficult to plan, execute, and finance. While a number of organizational types are transient-member nonprofits, youth sports organizations, are an archetype. This paper’s exploratory study sought to determine how such organizations’ transient characteristics appeared in their financial reports. It considered whether transient-member nonprofits report different profits, net assets, and liabilities when compared to more dedicated nonprofits. Transient-member nonprofits report lower net assets than do other nonprofits. An analysis of the degree to which organizations are transient found that the most transient organizations tend to have significantly lower net assets and liabilities. However, organizations that are relatively more transient do not report lower annual profits than other organizations

Experimental evaluation on noise reduction performance of a motorcycle helmet

Motorcycle helmets are generally thought to be only protection of motorcycle drivers against head injuries as well as loud noise in traffic. While there have been several papers on noise elimination capabilities of motorcycle helmets, no controlled study has been reported to compare different types of test conditions in literature. The purpose of this study is to assess noise reduction capacities of a motorcycle helmet under different types of acoustical loadings as well as environments and to identify better test condition. Firstly, a Head & Torso simulator with and without the motorcycle helmet in a built acoustical cabinet was exposed to digitally generated sound to investigate insertion loss values. Besides, the Head & Torso simulator was fixed onto a motorcycle to simulate actual driving conditions. Sound pressure levels were captured at the ear level to obtain insertion loss values in case of motorcycle noise for different engine speeds. By comparing calculated insertion losses, it was revealed that considerable differences existed between tests for different conditions. Beneficial interpretations were deduced and thus, a practical solution was presented for accurate measurements acoustic performance of the motorcycle helmets in laboratory conditions

Effects of combined general anesthesia and thoracic epidural analgesia on cytokine response in patients undergoing laparoscopic cholecystectomy

Background: Severe postoperative pain is not often experienced in laparoscopic cholecystectomy. Anesthesia, surgery, and pain are stressful and cause different reactions in neuro‑immuno‑endocrine systems. Many factors such as the pharmacological effect of the drugs used, as well as the type and depth of anesthesia, can affect these reactions.Objective: The aim of this study was to evaluate the effect of the combination of general anesthesia and thoracic epidural analgesia (TEA) on cytokine reaction in laparoscopic cholecystectomy.Study Design: Prospective, randomized clinical comparative study.Materials and Methods: Sixty adult patients scheduled for elective laparoscopic cholecystectomy were divided into four groups. Group saline (Group S), group fentanyl (Group F), group bupivacaine (Group B), and group levobupivacaine (Group L) were infused with saline, saline and fentanyl, bupivacaine and fentanyl, and levobupivacaine and fentanyl, respectively, via epidural catheter before surgical incision.Results: There were no differences among groups in the demographic features, heart rate, mean arterial pressure, and peripheral oxygen saturation values. Group L had lower visual analogue scale value compared to the other postoperative groups (P < 0.01). In all groups, interleukin‑6 (IL‑6), IL‑8, and IL‑10 levels started to increase at 2 h and returned to the basal level at 24 h. IL levels increased in most of the epidural saline‑administered group compared to other groups (P < 0.05).Conclusion: Combined general anesthesia and TEA provided pain control and hemodynamic stability more efficiently during the first 24 h of the intraoperative and postoperative period by suppressing cytokine levels. However, we determined that this effect was more obvious with the local anesthetic and opioid combination.Keywords: Bupivacaine, combined‑general‑epidural anesthesia, inflammatory cytokines, laparoscopic cholecystectomy, levobupivacain

Clinical Evaluation of Small Diameter Straumann Implants in Partially Edentulous Patients: A 5-Year Retrospective Study

Objective: The aim of the present study was to retrospectively evaluate small-diameter (3.3 mm) Straumann® dental implants placed in the maxilla or the mandible over a period of 5 years in function.Materials and Methods: Twenty- eight partially edentulous patients received a total of 48 implants over a 5-year period. After the standard healing period (3 to 6 months), the implants were restored with single-tooth prostheses or fixed partial dentures. All patients were followed according to a strict maintenance program with regular recalls. The cumulative survival rates of implants were analyzed and prosthetic complications were assessed.Results: After 5 years of function, one single 10-mm-long implant in the maxillary premolar region was lost because of recurrent peri-implant infection in a female patient. Two single 10-mm-long maxillary implants placed in the posterior region were lost due to body fracture. The cumulative 5-year survival rate of the implants was 93.75 %. The most common prosthetic complication was loosening of the occlusal screw.Conclusion: Within the limited observation period and the number of patients included in this study, it may be concluded that the use of small-diameter implants appears to be predictable if clinical guidelines are followed and appropriate prosthetic restorations are provided. However, it should be noted that fatigue fracture may occur